no, plain stain will do nothing to seal the wood, just changes color. Having said that, you can get products that are stain/sealer or perservative for things like decks and exterior surfaces. You can also seal it with products such as tung or mineral oil
With a bit more work on your part, you can end up with a beautiful cabinet.
The antique oil is more durable and easy enough to apply, about the easiest of anything I've used. It just take several coats. You spread it on with a cloth, let it sit five minutes and then buff it until it's not tacky anymore. Let dry 24 hours and apply again - each coat will deepen the luster as you are creating a smooth finish.
I've only gotten around to three sewing cabinet so far. And I've got one in pieces down in the basement. Most of my experience comes from doing all the woodwork and cabinetry in our house -though we have painted cabinets in the master bath and kitchen, and unfinished cedar in the second bath.
The best advantage I have is a shop full of higher end woodworking tools. I have a great Festool finish sander - it is the one that comes with a vacuum unit so I can use it in the house.
Here is the one I started this spring and haven't gotten back to yet - other than to bring it inside now that it's too cold to work in the shed.
I've got some veneer repair to do -and I know that is what's holding me up right now. I have all the tools so no reason to not get to it
This is has some beautiful wood grain - should be very nice when complete
Maybe following along with your progress will get me motivated.
This cabinet is sealed with Antique Oil, it gives it a deep, soft glow.
These two I put GF Salad Bowl finish on. It's a much more forgiving product to use than polyurethane, but also takes about 4 coats to get a decent sheen.
I think you'll be much happier with your results if you take the time up front to do a nice job. For me, putting on the finish is enough work that it is silly to do only a half job getting to that point. It's a lot harder to make things look nicer after you've stained and applied the finish.
I also understand fully how sometimes your "give a darn" just isn't where it should be LOL!!